Clamp-on electric heater



' 1,642,197 p 1927' P. FOWLER CLAMP-0N ELECTRIC HEATER Filed Nov. 10,1925 2 sheets she t 1 INVENTOR J CZQZIZO Irr W ATTORNEY Sept. 13, 1927.P. L. FOWLER CLAMP- ON ELECTRIC HEATER I 2 Sheets-Sheet 2 Filed. NOV.10, 1925 ATTORNEY Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE.

PAUL L. FOWLER 0F SPOKANE, WASHINGTON, ASSIGNOR TO ARTHUR-FOWLER 00., OFSPOKANE, WASHINGTON, A CORPORATION OF WASHINGTON.

Application filed November This invention relates to improvements inelectric water heaters for range boilers and has to do with that type ofheater of this class which is clamped about the periphery of the boiler,and therefore, has no bearing on cir culating heaters.

One of the features of my invention is to provide a novel form ofsupporting band for the heater, wherein a heating element and itsprotecting plate is disposed on' one face of said band, and wherein aheat insulating structureis disposed on the remaining face of said'band.

In a heater of this type, flexure without interference of parts, is agreat desideratum for the reason that these heaters are initially madeflat, and shipped and sold flat, and when they are installed, they arebent around and tensioned to firmly engage the periphery of the boiler.Now as the heater is made up of a plurality of band-like layers ofmaterial, it is a feature of my invention to connect these layers orintegers in such a manner that they can bodilv partake of relativelongitudinal displacement, due to flexure, without interference. Thisfeature of my invention also greatly facilitates assembling of theheater at the place of manufacture. This feature of my invention is alsoimportant by reason of the fact that the layers or integers of materialof which the heater is made up, are all of different material.

It is a feature of my invention to provide a heating element which iscompletely insulated, and to completely enclose said element on the tankor boiler side of the supporting band and also provide the latter with aterminal box whereto the terminals of the element are connected andextended through the supporting band for this purpose.

It is a further object of this invention to make the heaters of a givenor uniform length, irrespective of the heating capacity thereof, forboilers of different diameters,.

' and to provide means whereby the heaters may be clamped onto any ofthe usual SIZB' boilers.

The invention has many other objects and features which will be morefully described in connection with the accompanying drawings, and whichwill be more particularly pointed out in and by the app In the drawingsFig. 1 is a horizontal ended claims.

sectional view of a CLAMP-ON ELECTRIC HEATER.

1Q, 1925. Serial N0. 68,205.

range boiler showin the device of my invent1on clamped therea hout.

Fig. 2 IS a view in elevation, on an enlarged scale, showing the heaterflat, and look ng toward the tank or boiler side of the heater.

F 1g. 3 is a view of the heater looking to- Ward the outside facethereof.

Fig. 4 s a top edge view of the terminal end portion of the heaterlooking .downwardly on the left hand end portion of Fig. 2.

Fig. 5 is a similar view of the right hand 7 end portion of Fig. 2.

Fig. 6 is a sectional view on line 66 of Fig. 4. 1

Fig. 7 is a sectional view on line 7-7 of Fig. 4.

Fig. 8 is aview in elevation on a small scale showing how the integersof the heat insulating structure are united.

Fig. 9 is a view in elevation, on a small scale, of the heating elementshowing the manner of coiling the same and disposing the.

terminals near the end of said element. Fig. 10 is a view of the sameafter the inner envelope has been formed.

Fig. 11 is a sectional view on 1ine.1111 of Fig. 9. v

Like characters of reference designate similar parts throughout thedifferent figures of the drawings.

Referring to the specific form shown, 9. preferably metallic andflexible supporting band is employed having a central or main bodyportion 1. The terminal end 2, of said band 18 doubled or bent back uponor against the body portion 1, and secured in abutting relation as bymeans of rivets 3, thereby increasing the strength of the material atthis point. In the bight of the bend, as at 4, I dispose a rod 5, andwith suitable openings 6, I provide access for connection of clamp- I onchains 7, two being shown. The bent 10. In the wall of said box 8, is asuitable,

conduit opening 11, through which conductors may be extended forconnection with terminals in the box. A block of insulatin material 12,is disposed in said box 8, an may be anchored by screws 13 extendingthrough the block and through the support? against v tents and ing band,as shown in Fig. 6. Thus, it will be seen that the terminal box iscarrled by the supporting band and preferably at the terminal endthereof. Hereinafter, I Wlll refer to the manner in which the element iselectrically connected with terminal posts and secured as by rivets 16,to form a double thickness, and in the bi'ght 17, I dispose a rod 18.Coupling members 19, extend through openings'20, and around rod 18, todistribute the strain of the band. These coupling members are preferablyhook-shaped and in the hook ends thereof, shown at 21, are openings 22,for receiving tightening bolts, the nuts 23, thereof, impinging on theends 21. Said bolts have hooked ends for coupling engagement with chains7. Thus, by tightening the nuts, I.

have afforded means for clamping on a heater of uniform length, abouttanks of d1f ferent diameters. I

' The extreme or terminal end 24, is bent outwardly into spaced relationto body 1, to form an endpocket, in a manner simllar to end 14, saidends forming companion pock ets for a purpose which I will nextdescribe.

lVhile heaters of this type are applied to tanks or boilers which areenclosed by blankets or other form of enveloping insulation againstradiation of heat, still, it is an portant feature to provide specialinsulation heat radiation outwardly abreast of the electrical element. Itherefore employ an insulating structure on the outside 0 band 1, whichis generally indicated at 25, I preferably use asbestos, in thiscapaclty, but in the event of any type being used, it is advantageous toem loy a laminated or layer structure to obtam the benefit of air spacesintermediate .the layers. Because of the outer cover with which thetanks are equipped, there is no air circulation, hence theseintermediate air spaces are to all inurposes, dead air spaces, whichform the i Now it is well known that asbestos, especially in thick bandform, does not lend itself well to bending movement, and that it alsohas great friction against asbestos. Hence,-the problem of usingasbestos in a flexible heater that must be flexed, involves thenecessity of provision for relative displacement of the layers, and Ihave solved this problem in the followin manner.

As shown, I use four ban '-like strips of asbestos, the inner and outerbands 26, are

throughout the width f band, and I frictionally and slide.

est type against heat radiation.

relatively thin, and the two intermediate bands 27, are relativelythick. In'practice, these bands are disposed in flat abutting relationand because they are floatin ly supported, and also to afford relative'splacement of the bands, I unite the same preferably b luing themtogether substantially centrally between their ends, as indicated bydotted lines 28 in Fig. 8. Thus, all the integers are united to form aunitary insulating structure with the end portions 29, free fromconnection with each other. This structure 25, is disposed abreast ofthe outer face of supporting band 1, in the manner shown, with the endsof said structure in the open sided pockets formed 'by the supportingband ends 14 and 24. I preferably energize said ends 14 and 24, tolmpart a frictional grip 'on the structure 25, and as shown, this 1saccomplished by a plurality of tension springs 30, having their endssecured to the edges of parts 14 and 24. These springsout their lengthagainst the structure 25,

helping thus, to frictionally support the latter on the supporting band.When the heater is flat, the portions 31 and 32 impinge against the endsof the structure 25, to support the latter in place, and when the heateris flexed, the free end portions thereof move relatively to each otherbecause of the reater radii about which tht outer band nds, as regardsthe radii of the inner bands, and then tension is a plied not onlylengthwise by springs 30, an the friction of parts 14 and 24 isincreased artly by reason of the resistance of said ban s againstbending movement. At any rate, I floatingly mount the structure 25, onsaid sugporting ly support said structure thereon.

Before describin the structure of my improved heating e ement I willfirst refer to the same generally and will describe the means and mannerof its mounting in the heater. I

The element is designated at 33, and is disposed abreast of the insideface of band being shown in Fig. 2. The band 1, is shown reduced at 34,this reduction being the result of slitting the upper and lower marginsof band 1, to form the series of lugs 35. .lt will be noted that theband 1 .is slit to dispose the lugs 35 in spaced relation with respectto each other, their lateral and adjacent edges being free fromengagement. I employ what I will term, a hard surface heat conductingcontact band 36, preferably of'copper, said band being longer and widerthan the element 33, but of less width and length than body 1, of thesupporting band.

mm- M at...

, 1, the relative length and width of the two slidable mounting of thecontact plate or band 36, on the heater. The lugs 35, are disposedendwi'se of body 1, sufiicientlyto h old end portions of band 36 in fiatabutting xrelation against body 1, whereby the element 33, will becompletely enveloped by body 1 and band 36. It will be noted from Fig. 6that the upper and lower margins of ban 36 extend inwardly over theedgesof the element 33, so that the rectangular bulge formed in the band 36,by said element, may

' be uniformly pressed against the boiler with-- out any. interferenceon the part of the en the heater is flexed about the boiler, the spacesbetween lugs 35, avoid interference, and not only the contact band 36,but

. also the element and supporting band 1, can

placement necessitated by suc partake of the relative lon itudinaldisflexure. for any reason, it is necessary to remove or renew theelement, it is an easy matter to withdraw the slidably mounted contactband 36, to render the element accessible, without totally dismantlingthe heater or evensending it back to the manufacturer or place ofpurchase, and without extreme delay in hot water service to the user.Further the metallic-band 36, will wear practically indefinitely andfully protects the element from wear, therefore, I consider it animportant feature of my invention that the heating element is disposedinside or alongside a hard surface, high heat conducting or metalliccontact band, and, as shown, between a hard surface or metallicsupporting band and said contact band.

I will next refer to my improved heating element which I consider new,as an. article of manufacture, and also in the combina-' tion set forth.

Referring to-Figs. 9 to 11, 37 indicatessomewhat wider and longer thanthe sheet- 37. The element 39 is disposed in the manner shown, and bothterminals 40, are extended from one end of the structure. In practice, Ishellac or otherwise fix the wire to the sheet 37 and then placethereover, a similar sheet of asbestos 41, so that the coil is enclosed,first, in an asbestos casing. I then add an additional sheet of mica 42,of less width than sheet 38, so that the edges 43, of sheet 38, can bebent over, as shown in Fig. 11. In the drawings, I have shown thethickness of the materials greatly exaggerated, for clearness ofillustration, but the mica and asbestos sheets actually employed, are sothin that the resultant double envelope shown, practically has noprojections and is to all intents and purposes substantially fiat. I donot, in practice, secure the ends of the coils, which I will desi ate44, and -which are shown wavy in. ig. 9, but leave-them loose, not onlyto afford an extra length for connection with the terminal box, buttodnsure that there shall be no such connection between the heatingelement and the. heater such as would prevent the former from beingtruly .floatingly mounted in the latter whereby the heater maythusparticipate in the rela tive displacement necessitated by fiexure of"the heater. It will be clear, especially by referring to Figs. 6 and 7,that the contact late 36, is frictionally engaged against the e ement,and the latter is en aged against body 1, of the supporting band, throuhout thelength and width of the element. Ihus, with this constructionthere is no diificulty in obtaining a firm and uniform engagement ofthecontact band against the boiler.

As will be seen by Fig. 6, the terminals 40, are extended throughproperly insulated openings in the supporting band and through the block12, and are connected with binding posts 45, whereto the supplyconducting wires may also be connected, as will be clear to thoseskilled in the art.

Now it will be clear, that my heating element coil is mounted, andsubstantially fixed to an inner envelope of asbestos, or the like, andthe latter is encased in an envelope of mica, thereby providing a doubleinsulation, which, in actual service, stands up under the devastatingeffects oflightning, with less loss ofcoils than any heater of this typeknown to me. I

Further, this novel form of insulated heating element enables me todispose the same between, and encase it in metal, with the heretoforedescribed advantages of firm and uniform contact with the boiler. Onegreat advantage of using an outer envelope of mica, is that it presentsa hard finished surface to the metal and thereby facilitates movement ofthe. parts under flexure of the heater. 7

While I have described one specific form of my invention, I do not wishto be limited thereto except for such limitations as the claims mayimport.

I claim 1. In a flexible clamp-on electric heater for range boilers, aband-like insulated heating element, a thin contact band adapted to bedisposed a ainst the inner face of said element and a out the boiler andhaving a width and length in excess of that of said element, and asupporting band disposed along the outer face of said element and havingmeans engaging the upper and lower margins of said contact band to holdthe latter and said element in position, said means being disposedbeyond the margins of said element and flexing the end and side marginsof said thin contact band against said supporting band to envelope saidelement.

2. In a flexible clamp on electric heater for range boilers, a flexibleelectrically in-, sulated band-like heating element, and a flexiblesupporting band having means for supporting said element abreast of theinside face of said band, and said band having flexible means forsupporting a heat insulatin structure abreast of the outside face ofsaid band.

3. In a flexible clamp-on electric heater. for range boilers, a flexibleelectrically insulated band-like heater element, a metallic contact bandof greater length and width for range boilers,

than said heating band, and a flexible sup porting band having its upperand lower margins slit to form lugs adapted to be bent over and againstthe upper and lower margins of said contact band to dispose said marginsand also the ends of said contact band in abutting relation against saidsupporting band to completely enclose said heating element.

insulating material onto said supporting band. 7

5. In a flexible clamp-on electric heater a flexible supporting bandprovided with an electric heater; abreast of its inner face, band-likeinte of heat insulating material abreast of t e outer face of said banddisposed in abutting relation with the inte ers united between theirends,

and said ban having spring tensioned ends outwardly overlapping the endsof said integers to frictionally support said integers on said band andpermit relative longitudinal displacement of the ends of said integersas the heater is flexed about the periphery of the boiler.

6. In a flexible clamp-on electric heater for range boilers, a flexiblesupporting band rovided with an electric heater abreastjof 1 1ts innerface, end portions of said band being bent outwardly and back againstand secured to the outer face of the body of said band, a rod disposedin the bights of said bent over ends, means connected with said rods fortightening said band and its heater into snug engagement against theperiphery of a boiler, the terminal rtions of said outwardly bent endsbeing isposed in spaced relation to the band, and a heat insulatingstructure abreast of the outer face of said band and the ends of saidstructure being interposed between said band and said spaced terminals.

7 In a flexib'le clamp-on electric heater for range boilers, a flexiblesupporting band,

an electric heater element structure floatingly supported on the insideface of said band, and. a heat insulating structure floatiJngiysupported *on the outside face of said In testimony that I claim theforegoing as my own, I hereby aflix my signature.

PAUL L. FOWLER-l

